Flotation of minerals



Pa ented Mar. 26, 1935 PATENT OFFICE FLOTATIONQ F MINERALS Charles L.Bur-dick, Wilmington, Del.,assignor to E. I. du Pont de Nemours &Company, Wilmington, Del., a corporation of Delaware No Drawing.Application February 26, 1932,

Serial No. 595,432 7 6 Claims.

This invention relates to the treatment of ores, metallurgical productsand like heterogeneous materials containingcompounds of the useful ormore or" less valuable metals and has for its object to provideimprovements in the separation of the compounds in question by flotationand particularly by froth flotation from the less valuable components ofthe mate'rialstreated.

Hitherto many proposals have been made for the wet concentration of oresinvolving the addition to the liquid in which the ore is suspended of afrothing agent. Other agents have likewise been added to the frothingagent, e. g. promoters,

depressors, regulators, activators, dispersers, etc.,these latter namedagents being used to aid the flotation agent in separating the mineralpar?- ticles from the gangue and to enable more perfect selection ordifferentiation between the mineral components of the mixture. Myinvention is primarily directed to the flotation agent with which theother above named agents may be employed if found desirable. a I

Gaudin, Haynes, and Haas (Technical Paper No. 7, Mining & MetallurgicalInvestigations, University of Utah, 1930) 1 have conducted a; number ofinvestigations on frothing agents and state: The quality most sought forin frothing agents is the production of a foam, barren yet able tosupport a mineral load and of suflicient brittleness to break downrapidly after the supply of bubbles is exhausted. Many of the frothingagents now being commercially employed,

such, for example, as pine oil, creosole, eucalyptus oil, etc., arecapable of developing a suflicient froth to separatethe mineralparticles from the ganguebut dueto the relatively tough'and permanentnature of the froth formed, considerable difliculty is encountered incollapsing the froth in order to separate the mineral particlestherefrom.

An object of the present invention is to provide a new and improvedfrothing agent which does not havethe inherent disadvantages of thefrothing agents now being employed. Another object of the presentinvention is to provide a frothing agentwhich will develop a brittle andimpermanent froth of suflicient buoyancy to float the mineral particlesand yet of such an impermanent nature that upon removal from theagitating apparatus it rapidly and completely collapses, thus affordingeasy separation of the min-' eral particles therefrom. A still furtherobject of the invention is to provide .a new and improved frothing agentcomprising a mixture of oxygen-'- ated organic compounds obtained fromthe catavated pressure.

-' the Williams patent or like processes, which I prelytic hydrogenationof carbon oxide under ele- Other objects will hereinafter app a 4 Myinvention is based upon the discoveryvthat the flotation operation can,in many cases, be 5 improved by'the addition to the ore or mineral pulpof oxygenated organic compounds obtained by the catalytic'hydrogenationof carbon monoxide under elevated temperatures and pressures as theflotation agent, My flotation agent may 10 be used alone forthetreatment of many oreswhile inthe treatment ofothers it isadvantageousto use it in conjunction with the other agents usuallyemployed in like processes.

Furthermore, if other flotation agents are 15 used, such as pine oil,eucalyptus oil, or any flotation agent which develops a permanent froththat-does not collapse as rapidly as desired, after removal with themineral particles separated from 'the ganguefromthe flotation chamber,the addition of my flotation agent to this stable froth will hasten itscollapse. When using my flotation agent in this manner it may be addedprior to, during, or subsequent to the flotation operation.

My preferred frothing agent is derived from the following source. In thecatalytic hydrogenation of carbon oxide under elevated temperatures andpressures a variety of straight and branch chained organic compoundscontaining oXygen are made. These organic compounds have a boiling.pbint ranging from about 50 C. to a temperature of 250 C. and higher.

Various methods have been proposed for the manufacture of theseoxygenated organic compounds, for example a method for their synthesisis described in the U. S. Patent of Roger Williams No. 1,820,417. Thefractions of the oxygenated organic compounds obtained by the process of40 fer to use, are those boiling from a temperature of approximately C1up.

The oxygenated organic, compounds boiling from 130 C. up have beenfractionated systematically-into a series of fractions, namely 130 to147; 45 147 to 157 157 to 195' to 240; and 240 up.

As would be expectedthese various fractions difin their flotationability in degree rather than with the ore or mineral pulp in anysuitableone being highly suitable while another being ,absolutelyunsuited for a particular operation.

The fraction to be used may be incorporated manner which will ensure itsuniform incorporation and dissemination thruout the pulp. It may 'thusbe incorporated by adding to the grinding mill, in which the ore isground, or it may be added after the grinding operation and during orprior to the flotation operation. The flotation operation can be carriedout in any suitable ap-' paratus, such as .an ordinary Callow cell, orin apparatus where the air is incorporated in the ore pulp by mechanicalagitation.

1 The following is given by way of example of the process but it will beunderstood thatl am not limited by the details thereof. One' hundredparts by weight of lead-zinc ore slimes (sulphide) containing 20% ofmetal are treated alone or after'being admixed with of iron ore withapproximately 2 parts byweight of the oxygen.-

, ated organic compounds boiling from 130 C. up.

After thorough mixing the magma is passed into an apparatus where air isincorporated with the ore pulp by mechanical. agitation. There thentakes place a coinpleteseparation of the crude iron ore and gangue, onthe one hand, and of the sulphide ores, on the other, inasmuch as theseores rise to the surfacewhile the iron-ore and the gangue sink to thebottom of the apparatus. The refuse is continually removed from thebottomand the floating ores are collected from the top upon strainers.The froth and entangled mineral particles overflow from the zone ofagitation to the launder of the flotation machine wherein a rapid andthorough collapse of the froth occurs which facilitates furthertreatment of the mineral particles. 7 s

It is sometimes advisable to provide a selective ore collecting agent tosupplement the action of the oxygenated organic compounds employed, asthese compoundsappear to be essentially frothing agents. Where, however,the .ore pulp contains an appropriate selective or collecting agent, orinherently requires the addition of no such agentfbutis eflicient infrothing qualities, the

' addition of my improved frothing agent in a manner similar to thatabove described, imparts the desired frothing. qualities and providesbubbles in a suflicient quantity and of a sufllcient persistency tooverflow into .the launder of the flotation machine, therebymechanically facilitating the removal of the, mineralconcentrate'.

In some cases where it is advantageous to employ the higher boilingfractions of my flotation agent, Ihave found it advisable to incorporatetherewith-a solubilizing or disseminating agent,

particularly when the frothing agent is added directly to the flotationmachine. These solubilizers shouldpreferably be not only miscible withthe higher boiling fractions but also miscible with water in order toaid in the dispersion of the flotation agent. The lower boiling alcoholssuch as methanol and ethanol and, in some instances, the lower boil-ingfractions of the oxygenated or ganic compounds above described, areexamples of suitable solu'bilizers. y Any improvement inthe process orproducts a e at elevated pressures.

disclosed in the above specificatio'nand described in the claims willcome within thescope of this invention without sacrificing any of theadvantages that may be derived therefrom.

. I claim:

1. The method of efiecting the concentration" of minerals byfroth-flotation, which comprises 'the resulting mixture to a flotationoperation.

3; The method of eifecting the concentration 6f minerals byfroth-flotation, which comprises adding to the mineral pulp a smallamount of the oxygenated organic compounds having a boiling range fromapproximately 240 C. up, and which were obtained by the catalytichydrogenation of,

carbon oxides under high pressure and a solubilizer comprising theoxygenated organic compounds having a boiling range from approximately130- C.

to approximately 195 C. which also was obtained by the catalytichydrogenation of carbon oxides under elevatedpressure, and subjectingthe resulting mixture to a flotation operation.

4. In 'a process of eifecting the" concentration f of minerals byfroth-flotation which involves the separation of 'mineral particles fromthe gangue by the froth formed as the result of the addition to the ore"of a flotation agent and subsequent removal of the mineral particle andfroth from the zone of flotation for final segregation of the mineralparticles, the step which comprises employing in the.process a'fractionof the oxygenated organic compounds boiling above 130 C. obtained by thecatalytic hydrogenation of carbon oxide under elevated pressures.

5. 'I'hemethod of eifecting the concentration of minerals byfroth-flotation, which comprisesadding to the vmineral pulpapproximately 2% by weight of the oxygenated organic compounds boilingabove 130 C., the compoundshaving been obtained by the catalytichydrogenation of carbon oxide under high pressure, and subjecting" theresulting mixture to a flotation operation.

6. In a,process of 'efl'ecting the concentration of minerals byflotation, which involves the 'separationv of mineral particles from,the gangue by the froth formed as the result of the addition to the oreof aflotation agent and subsequent removal of the mineral particles andfroth from the zone of flotation for final segregation of the mineralparticles, the step which comprises employing in the processapproximately 2% by weight of a fraction of the oxygenated organiccompounds boiling above 130 Cl and obtained'by the catalytichydrogenation of carbon oxide under CHARLES" L. BURDICK.

